Introduction: Traditional treatment for chronic subdural hematoma (cSDH) has been surgical evacuation with burr holes or craniotomies, but recurrence rates can be high and patients often harbor complex medical comorbidities. Growth and recurrence is thought to be due to the highly vascularized nature of the 2-3 layered membrane that forms after initial injury with possible communication with the middle meningeal artery (MMA). There have been reported cases in Asia of MMA embolization for treatment of recurrent cSDH after surgical evacuation with the goal of eliminating the arterial supply to this vascularized membrane. We present the first known case series of MMA embolization as upfront treatment for cSDH in lieu of surgical evacuation that has failed conservative management.

Methods: 5 patients with symptomatic cSDH underwent MMA embolization at our institution in 2015 by accessing the MMA with a microcatheter and injecting 150-250 micron PVA microparticles until significant stasis of anterograde flow was noted. cSDH membrane was sent from the operating room in another patient to pathology for histological analysis.

Results: 4 patients underwent unilateral and 1 underwent bilateral MMA embolization. All were successful and without complication. Post-procedure day 1 CT scans were all stable to slightly improved. All cases had significant reduction in size at longest follow up scan: 26 to 9mm at 8 weeks, 20 to 7mm at 2.5 weeks, 8 and 13 to 0 and 9mm at 6 weeks (bilateral), 16 to 9mm at 7 weeks, and 11 to 0mm at 6 weeks (Table 1, Figure 1). All patients had symptomatic relief at longest follow up. Histologic analysis revealed rich neovascularization within the membrane with many capillaries and few small arterioles (Figure 2).

Conclusions: MMA embolization could present a minimally invasive and low-risk alternative to surgery for symptomatic cSDH when clinically appropriate as demonstrated in our novel series of 5 patients.

Patient Care: MMA embolization could provide a safe, minimally invasive method for treatment of chronic subdural hematoma with low risk and minimal complications. This provides an alternative to surgical evacuation which often carries high risk in medically complex patients.

Learning Objectives: To demonstrate that middle meningeal artery embolization could provide a safe and effective way to treat chronic subdural hematoma as a first line treatment in select patients by describing our series of 5 patients.

References: 1. Hashimoto T, Ohashi T, Watanabe D, Koyama S, Namatame H, Izawa H, Haraoka R, Okada H, Ichimasu N, Akimoto J, Haraoka J. Usefulness of embolization of the middle meningeal artery for refractory chronic subdural hematomas. Surgical Neurology International. Surg Neurol Int. 2013 Aug 19;4:104 2. Tempaku A, Yamauchi S, Ikeda H, Tsubota N, Furukawa H, Maeda D, Kondo K, Nishio A. Usefulness of interventional embolization of the middle meningeal artery for recurrent chronic subdural hematoma: Five cases and a review of the literature. Interv Neuroradiol. 2015 May 26. 3. Tanaka T, Kaimori M. Histological study of vascular structure between the dura mater and the outer membrane in chronic subdural hematoma in an adult. No Shinkei Geka. 1999 May;27(5):431-6.